1. Field of the Invention
The present invention relates to power saws and more particularly to an indexed reciprocating saw for cutting truss webs.
Unitized structural floor and roof trusses are frequently used when constructing wood buildings, such as barns, residences, garages, etc.. These trusses are constructed from dimensional lumber, such as 2.times.4's or 2.times.6's, wherein the truss members are joined by metal plates and it is necessary that predetermined dimensions and angles of cuts be maintained to insure tight fitting truss joints. Without such tight fitting joints the truss components flex under loads imposed thereon and sometimes fail as a result of the loss of strength.
2. Description of the Prior Art
It has been common practice to cut one angle on the ends of a plurality of truss webs with the saw set at the predetermined angle and pass the webs by the saw after indexing it to cut the companion angle on the respective truss web ends. Another method is to cut both angles on each end of the truss by indexing a miter-type saw following each cut. Either way requires at least one workman and is a time consuming operation frequently resulting in variations of the length of some of the webs with respect to companion webs.
The most pertinent prior art patent is believed U.S. Pat. No. 4,036,093 which discloses a power saw cycled vertically in a reciprocating mode after being set at a predetermined cutting angle relative to the workpiece which is maintained stationary by a work positioner and power workpiece clamp. The power saw is reciprocated by a pair of continuous running motors selectively clutch engaged manually with a threaded screw operatively connected with a power saw frame for lowering the power saw by one of the two motors and raising the power saw by the other one of the two motors.
This invention is distinctive over prior art web saws and the above named patent by providing a vertically reciprocating power saw operating on a workpiece clamped in a predetermined position in which the power saw may be set at predetermined cutting angles disposed in 90.degree. relationship wherein the saw forms one of the web end cuts on its downstroke and the companion cut on its upstroke thus completing the 90.degree. spaced angle cuts on adjacent ends of two webs cut from the workpiece.